The Great Barrier Reef Marine Park Authority seeks to develop a socio-economic monitoring program, but there are a vast number of variables (or ‘indicators’) that could, potentially, be monitored and monitoring is not a costless exercise. So, it is important to ensure that the variables selected for ‘monitoring’, are ones which, (a) provide reliable, relevant information, which (b) measure interactions between sub-systems (e.g. socio-economic and biophysical) and which (c) are clearly associated with the Authority’s primary goal of protecting the Reef, i.e.